/*	$OpenBSD: paste.c,v 1.26 2018/08/04 19:19:37 schwarze Exp $	*/

/*
 * Copyright (c) 1989 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Adam S. Moskowitz of Menlo Consulting.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <queue.h>
#include <sys/types.h>
#include <err.h>
#include <errno.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "compat.h"

char *delim;
int delimcnt;

int tr(char *);
void usage(void);
void parallel(char **);
void sequential(char **);

int main(int argc, char *argv[]) {
  setprogname(argv[0]);
  extern char *optarg;
  extern int optind;
  int ch, seq;

  seq = 0;
  while ((ch = getopt(argc, argv, "d:s")) != -1) {
    switch (ch) {
      case 'd':
        delimcnt = tr(delim = optarg);
        break;
      case 's':
        seq = 1;
        break;
      case '?':
      default:
        usage();
    }
  }
  argc -= optind;
  argv += optind;

  if (argc == 0) usage();

  if (delim == NULL) {
    delimcnt = 1;
    delim = "\t";
  }

  if (seq)
    sequential(argv);
  else
    parallel(argv);
  return 0;
}

struct list {
  SIMPLEQ_ENTRY(list) entries;
  FILE *fp;
  int cnt;
  char *name;
};

void parallel(char **argv) {
  SIMPLEQ_HEAD(, list) head = SIMPLEQ_HEAD_INITIALIZER(head);
  struct list *lp;
  char *line, *p;
  size_t linesize;
  ssize_t len;
  int cnt;
  int opencnt, output;
  char ch;

  for (cnt = 0; (p = *argv) != NULL; ++argv, ++cnt) {
    if ((lp = malloc(sizeof(*lp))) == NULL) err(1, NULL);

    if (p[0] == '-' && p[1] == '\0')
      lp->fp = stdin;
    else if ((lp->fp = fopen(p, "r")) == NULL)
      err(1, "%s", p);
    lp->cnt = cnt;
    lp->name = p;
    SIMPLEQ_INSERT_TAIL(&head, lp, entries);
  }

  line = NULL;
  linesize = 0;

  for (opencnt = cnt; opencnt;) {
    output = 0;
    SIMPLEQ_FOREACH(lp, &head, entries) {
      if (lp->fp == NULL) {
        if (output && lp->cnt && (ch = delim[(lp->cnt - 1) % delimcnt]))
          putchar(ch);
        continue;
      }
      if ((len = getline(&line, &linesize, lp->fp)) == -1) {
        if (ferror(lp->fp))
          err(1, "%s", lp->fp == stdin ? "getline" : lp->name);
        if (--opencnt == 0) break;
        if (lp->fp != stdin) fclose(lp->fp);
        lp->fp = NULL;
        if (output && lp->cnt && (ch = delim[(lp->cnt - 1) % delimcnt]))
          putchar(ch);
        continue;
      }
      if (line[len - 1] == '\n') line[len - 1] = '\0';
      /*
       * make sure that we don't print any delimiters
       * unless there's a non-empty file.
       */
      if (!output) {
        output = 1;
        for (cnt = 0; cnt < lp->cnt; ++cnt)
          if ((ch = delim[cnt % delimcnt])) putchar(ch);
      } else if ((ch = delim[(lp->cnt - 1) % delimcnt]))
        putchar(ch);
      fputs(line, stdout);
    }
    if (output) putchar('\n');
  }
  free(line);
}

void sequential(char **argv) {
  FILE *fp;
  char *line, *p;
  size_t linesize;
  ssize_t len;
  int cnt;

  line = NULL;
  linesize = 0;
  for (; (p = *argv) != NULL; ++argv) {
    if (p[0] == '-' && p[1] == '\0')
      fp = stdin;
    else if ((fp = fopen(p, "r")) == NULL) {
      warn("%s", p);
      continue;
    }
    cnt = -1;
    while ((len = getline(&line, &linesize, fp)) != -1) {
      if (line[len - 1] == '\n') line[len - 1] = '\0';
      if (cnt >= 0) putchar(delim[cnt]);
      if (++cnt == delimcnt) cnt = 0;
      fputs(line, stdout);
    }
    if (ferror(fp)) err(1, "%s", fp == stdin ? "getline" : p);
    if (cnt >= 0) putchar('\n');
    if (fp != stdin) fclose(fp);
  }
  free(line);
}

int tr(char *arg) {
  int cnt;
  char ch, *p;

  for (p = arg, cnt = 0; (ch = *p++) != '\0'; ++arg, ++cnt) {
    if (ch == '\\') {
      switch (ch = *p++) {
        case 'n':
          *arg = '\n';
          break;
        case 't':
          *arg = '\t';
          break;
        case '0':
          *arg = '\0';
          break;
        default:
          *arg = ch;
          break;
      }
    } else
      *arg = ch;
  }

  if (cnt == 0) errx(1, "no delimiters specified");
  return cnt;
}

void usage(void) {
  extern const char *__progname;
  fprintf(stderr, "usage: %s [-s] [-d list] file ...\n", __progname);
  exit(1);
}
